The mainstream media has reported over the past few days that the copyright negotiations between Viacom, the parent company of Nickelodeon, and YouTube have broken down. Here is an article on MSN that gives the basics.

When the talks broke down, Viacom sent a letter to YouTube demanding that they take down every video that has any kind of Viacom content in it, including, of course, Avatar. Based on the emails we've been getting and the posts on the forum, YouTube has decided to take the safe path and comply. Most if not all Avatar fanvids have been wiped out in the last few days.

Our condolences to all the fanvid makers out there, you guys do great work for the fandom!